MVC學習系列——Filter擴展

     在MVC中，Filter也是可以擴展的。在此，本人對Filter的理解就是AOP，不知道各位大俠，有什麼高的見解，呵呵。。。

首先MVC四大過濾神器IAuthorizationFilter，IActionFilter，IResultFilter，IExceptionFilter。

在此之前，我們先安裝Log4net日誌神器：

看下項目的引用

配置文件

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <configuration>
 3   <configSections>
 4     <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
 5   </configSections>
 6   <log4net>
 7     <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
 8       <!--日誌路徑-->
 9       <param name= "File" value= "D:\App_Log\"/>
10       <!--是否是向文件中追加日誌-->
11       <param name= "AppendToFile" value= "true"/>
12       <!--log保留天數-->
13       <param name= "MaxSizeRollBackups" value= "10"/>
14       <!--日誌文件名是否是固定不變的-->
15       <param name= "StaticLogFileName" value= "false"/>
16       <!--日誌文件名格式為:2008-08-31.log-->
17       <param name= "DatePattern" value= "yyyy-MM-dd&quot;.log&quot;"/>
18       <!--日誌根據日期滾動-->
19       <param name= "RollingStyle" value= "Date"/>
20       <layout type="log4net.Layout.PatternLayout">
21         <param name="ConversionPattern" value="%d [%t] %-5p %c - %m%n %loggername" />
22       </layout>
23     </appender>
24     <!-- 控制台前臺顯示日誌 -->
25     <appender name="ColoredConsoleAppender" type="log4net.Appender.ColoredConsoleAppender">
26       <mapping>
27         <level value="ERROR" />
28         <foreColor value="Red, HighIntensity" />
29       </mapping>
30       <mapping>
31         <level value="Info" />
32         <foreColor value="Green" />
33       </mapping>
34       <layout type="log4net.Layout.PatternLayout">
35         <conversionPattern value="%n%date{HH:mm:ss,fff} [%-5level] %m" />
36       </layout>
37 
38       <filter type="log4net.Filter.LevelRangeFilter">
39         <param name="LevelMin" value="Info" />
40         <param name="LevelMax" value="Fatal" />
41       </filter>
42     </appender>
43     <root>
44       <!--(高) OFF > FATAL > ERROR > WARN > INFO > DEBUG > ALL (低) -->
45       <level value="all" />
46       <appender-ref ref="ColoredConsoleAppender"/>
47       <appender-ref ref="RollingLogFileAppender"/>
48     </root>
49   </log4net>
50   <system.web>
51     <compilation debug="true" targetFramework="4.5.2" />
52     <httpRuntime targetFramework="4.5.2" />
53   </system.web>
54 </configuration>

增加LogHelper幫助類

 1  public class LogHelper
 2     {
 3         public static void WriteLog_Error(Type t, Exception ex)
 4         {
 5             log4net.ILog log = log4net.LogManager.GetLogger(t);
 6             log.Error("Unhandled exception", ex);
 7         }
 8 
 9         public static void WriteLog_Error(Type t, string msg)
10         {
11             log4net.ILog log = log4net.LogManager.GetLogger(t);
12             log.Error(msg);
13         }
14 
15         public static void WriteLog_Info(Type t, string msg)
16         {
17             log4net.ILog log = log4net.LogManager.GetLogger(t);
18             log.Info(msg);
19         }
20     }

還有一個重要的一步，在Gobal類中，要申明：

1 //載入配置文件
2             var logCfg = new FileInfo(AppDomain.CurrentDomain.BaseDirectory + "Log4Net.config");
3             XmlConfigurator.ConfigureAndWatch(logCfg);

ok，到這裡log4net，配置完成。

現在，我來擴展IExceptionFilter這個過濾器。

新建Log4NetExceptionFilter類，繼承介面IExceptionFilter

1 public class Log4NetExceptionFilter : IExceptionFilter
2     {
3         public void OnException(ExceptionContext filterContext)
4         {
5             LogHelper.WriteLog_Error(GetType(), filterContext.Exception);
6         }
7     }

在FilterConfig中申明自己的異常處理：

1  public class FilterConfig
2     {
3         public static void RegisterGlobalFilters(GlobalFilterCollection filters)
4         {
5             //filters.Add(new HandleErrorAttribute());
6             //加上自己的異常
7             filters.Add(new Log4NetExceptionFilter());
8         }
9     }

測試：在HomeController的GetXmlResult，手工增加異常：

 1  public XmlResult GetXmlResult()
 2         {
 3             int a = 1;
 4             int b = 0;
 5             int c = a / b;
 6 
 7             StudentViewModel viewModel = new StudentViewModel();
 8             viewModel.ID = "1";
 9             viewModel.Name ="Zhangsan";
10             viewModel.Gender = "Man";
11 
12             return new XmlResult(viewModel);
13         }

結果：

在介紹一下ActionFilterAttribute，這個特性有兩個介面IActionFilter, IResultFilter。

因此，新建MyActionFilterAttribute，繼承於ActionFilterAttribute

 1 public class MyActionFilterAttribute: ActionFilterAttribute
 2     {
 3         public override void OnActionExecuting(ActionExecutingContext filterContext)
 4         {
 5             LogHelper.WriteLog_Info(GetType(), "OnActionExecuting");
 6             base.OnActionExecuting(filterContext);
 7         }
 8         public override void OnActionExecuted(ActionExecutedContext filterContext)
 9         {
10             LogHelper.WriteLog_Info(GetType(), "OnActionExecuted");
11             base.OnActionExecuted(filterContext);
12         }
13 
14         public override void OnResultExecuting(ResultExecutingContext filterContext)
15         {
16             LogHelper.WriteLog_Info(GetType(), "OnResultExecuting");
17             base.OnResultExecuting(filterContext);
18         }
19 
20         public override void OnResultExecuted(ResultExecutedContext filterContext)
21         {
22             LogHelper.WriteLog_Info(GetType(), "OnResultExecuted");
23             base.OnResultExecuted(filterContext);
24         }
25     }

測試：在HomeController的GetXmlResult的方法上，增加MyActionFilterAttribute特性。ps:這裡已經去掉剛剛手工增加的異常。

  [MyActionFilterAttribute]
        public XmlResult GetXmlResult()
        {
            StudentViewModel viewModel = new StudentViewModel();
            viewModel.ID = "1";
            viewModel.Name ="Zhangsan";
            viewModel.Gender = "Man";
            return new XmlResult(viewModel);
        }

結果：